Intaglio printing machine and intaglio printing method

ABSTRACT

An intaglio printing machine provided with a plate cylinder ( 14 ), a wiping roller ( 19 ), an impression cylinder ( 13 ), and ink devices ( 17 ) for directly or indirectly supplying ink (I) from ink fountain devices ( 25 ) to the plate cylinder ( 14 ), and in which the ink devices ( 17 ) are provided with an ink fountain device ( 25 ) equipped with: an ink fountain roller ( 26 ); an ink-fountain-roller driving motor ( 42 ); an ink fountain ( 30 ) for storing ink (I); an ink fountain key ( 33 ), which is supported on the front end of the ink fountain ( 30 ) so as to move freely and is for adjusting the gap (G) between the ink fountain ( 30 ) and the ink fountain roller ( 26 ); and an ink-fountain-key adjusting motor ( 43 ) for adjusting amount of movement of the ink fountain key ( 33 ). The intaglio printing machine is provided with a control device ( 40 ) for controlling the ink-fountain-key adjusting motor ( 43 ) and ink-fountain-roller driving motor ( 42 ) so that prior to printing on a sheet (W), the ink fountain key ( 33 ) is closed and the ink fountain roller ( 26 ) is rotated.

TECHNICAL FIELD

The present invention relates to an intaglio printing press and anintaglio printing method. The present invention relates morespecifically to an intaglio printing press including an ink fountaindevice in an inking device configured to supply ink onto an intagliocylinder, and to an intaglio printing method of printing a sheet bysupplying ink from an ink fountain onto an intaglio cylinder through anink fountain roller.

BACKGROUND ART

An intaglio printing press of this type is disclosed in Patent Document1, for example.

It includes an ink fountain roller which is rotatably supported on aneccentric bearing, and a bottom plate (ink fountain keys) which isprovided at such a position that the front end thereof is located in theproximity of the ink fountain roller and which forms a gap between thisfront end and the peripheral surface of the ink fountain roller tosupply ink. By turning the eccentric bearing with ink-fountain-rollermoving means, the gap between the ink fountain roller and each inkfountain key can be adjusted by the same amount at once. In this way,the amount of ink to be supplied from the ink fountain onto the inkfountain roller can be adjusted in a short period of time, and wastedsheets can be reduced as well.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese Patent Application Publication No.2006-321129

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

Meanwhile, in the intaglio printing press, during printing, ink oozesfrom the position in the ink fountain device where the ink fountain keyand the ink fountain roller face each other, and the ink hardens. Whenthe printing is stopped, that ink combines with the ink on the inkfountain roller and is thereby formed as an ink residue. In the case ofintaglio printing, particularly indirect intaglio printing using an inkcollecting cylinder, low viscosity ink is used. For this reason,starting printing with the above an ink residue formed on the inkfountain roller leads to a problem in that a portion with uneven inkfilm thicknesses is formed due to the ink residue, thereby deterioratingthe printing quality. Note that a similar problem will occur also indirect intaglio printing using no ink collecting cylinder if lowviscosity ink is used.

How the above poor printing occurs will be described with reference toFIG. 7. FIG. 7 shows situations in each of which ink I supplied onto aplate P from an inking device not shown is transferred (printed) onto asheet (paper sheet) W. Here, Parts (a), (e), and (i) of FIG. 7 show astep where the ink I is supplied onto the plate P from the inkingdevice; Parts (b), (f), and (j) of FIG. 7 show a step where the plate Pis wiped by a wiping roller not shown; Parts (c), (g), and (k) of FIG. 7show a step where the ink I remaining inside a groove in the plate P istransferred onto the sheet W; and Parts (d), (h), and (l) of FIG. 7 showa step where the sheet W with the ink I transferred thereon is separatedfrom the plate P.

As can be seen from FIG. 7, in a case (x) where direct intaglio printingis performed using high viscosity ink, the ink I supplied on the plate Pis finely wiped and thereby neatly remains inside the groove (imageportion) in the plate P (see the steps from Parts (a) to (b)). Thisremaining ink I is finely transferred onto the sheet W (see the stepsfrom Parts (b) to (c) to (d)).

On the other hand, in cases (y) and (z) where indirect intaglio printingis performed using low viscosity ink, the following occurs.Specifically, in the case (y) where no ink residue is formed on the inkfountain roller of the ink fountain device, the ink I remainssubstantially neatly inside the groove in the plate P when wiped and istransferred finely onto the sheet W by going through the “good” stepsfrom Parts (e) to (f) to (g) to (h). However, in the case (z) where, inPart (i), an ink residue C, which is hardened high viscosity ink, isformed in the groove (image portion) in the plate P, poor printingoccurs as a result of going through the “bad” steps from Parts (j) to(k) to (l). Specifically, in the step in Part (j), the wiping cannot bedone finely with the wiping roller for low viscosity ink and, with theink residue C, a larger portion of the ink I remains inside the groovein the plate P. The ink I then sticks out from the groove in the plate Pand is transferred as is onto the sheet W in the steps from Parts (k) to(l). This results in a blur image and thus poor printing.

In view of the above, an object of the present invention is to providean intaglio printing press and an intaglio printing method capable ofeffectively solving problems caused by ink residues in an ink fountaindevice before the sheet is printed.

Means for Solving the Problem

To achieve the above object, an intaglio printing press according to thepresent invention is an intaglio printing press, including

an intaglio cylinder on which a plate is mounted,

a wiping roller configured to wipe an excess portion of ink on the plateby contacting the plate on the intaglio cylinder,

an impression cylinder configured to print a sheet by facing theintaglio cylinder, and

an inking device configured to supply ink directly or indirectly ontothe intaglio cylinder,

the inking device including

an ink fountain roller,

ink-fountain-roller driving means for rotationally driving the inkfountain roller,

an ink fountain a front end of which faces the ink fountain roller andwhich is configured to store ink in cooperation with a peripheralsurface of the ink fountain roller,

an ink fountain key movably supported on the front end of the inkfountain and configured to adjust a gap between the ink fountain key andthe ink fountain roller, and

ink-fountain-key adjusting means for adjusting an amount of movement ofthe ink fountain key,

characterized in that the intaglio printing press comprises a controldevice configured to control the ink-fountain-key adjusting means andthe ink-fountain-roller driving means before the sheet is printed, insuch a way as to rotationally drive the ink fountain roller with the inkfountain key closed.

The intaglio printing press may be characterized in that the intaglioprinting press is an indirect intaglio printing press comprising:

a plurality of chablon rollers onto which ink is transferred from theinking device; and

an ink collecting cylinder configured to transfer the ink from theplurality of chablon rollers onto the intaglio cylinder.

The intaglio printing press may be characterized in that the intaglioprinting press further comprises a form-roller throw-on and throw-offdevice configured to throw form rollers on and off the chablon rollers,and

the control device controls the form-roller throw-on and throw-offdevice in such a way as to throw the form rollers off the chablonrollers, when rotationally driving the ink fountain roller with the inkfountain key closed before printing is started.

The intaglio printing press may be characterized in that the controldevice controls the ink-fountain-key adjusting means and theink-fountain-roller driving means during printing in such a way as torotate the ink fountain roller with the ink fountain key moved to aproximity of the ink fountain roller.

The intaglio printing press may be characterized in that

the intaglio printing press further comprises an input switch configuredto start collection of ink, and

the control device controls the ink-fountain-key adjusting means and theink-fountain-roller driving means based on the input switch.

The intaglio printing press may be characterized in that

the intaglio printing press further comprises a counter configured tocount the number of printed sheets, and

the control device controls the ink-fountain-key adjusting means and theink-fountain-roller driving means based on the counter.

The intaglio printing press may be characterized in that

the intaglio printing press further comprises a film thickness detectorconfigured to detect an ink film thickness on the roller of the inkingdevice,

the control device controls the ink-fountain-key adjusting means and theink-fountain-roller driving means based on the film thickness detector.

The intaglio printing press may be characterized in that

the intaglio printing press further comprises a check device configuredto check a printed sheet, and

the control device controls the ink-fountain-key adjusting means and theink-fountain-roller driving means based on the check device.

To achieve the above object, an intaglio printing method according tothe present invention is an intaglio printing method of printing a sheetby supplying ink from an ink fountain onto an intaglio cylinder throughan ink fountain roller while passing the sheet between the intagliocylinder and an impression cylinder facing the intaglio cylinder,characterized in that the intaglio printing method comprisesrotationally driving the ink fountain roller while closing an inkfountain key before the sheet is printed, the ink fountain key beingconfigured to adjust a gap between the ink fountain key and the inkfountain roller.

The intaglio printing method may be characterized in that the intaglioprinting method further comprises rotationally driving the ink fountainroller while moving the ink fountain key to a proximity of the inkfountain roller during printing.

Effects of the Invention

In the intaglio printing press according to the present invention, theink fountain roller is rotationally driven for a predetermined period oftime with the ink fountain key in the ink fountain device closed (theamount of opening of the ink fountain key is set to zero) after theprinting press is operated but before the sheet is printed. In this way,the ink on the rollers in the inking device is returned into the inkfountain (this will be referred to as “fountain return”) and the ink onthe ink fountain roller can therefore be thinly leveled (reset). Hence,when the sheet is subsequently printed, fine printing is done owing tothe even ink film thickness. That is, problems caused by ink residuesformed on the ink fountain roller are solved.

Moreover, in the intaglio printing press according to the presentinvention, the ink fountain roller is rotationally driven for apredetermined period of time with the ink fountain key in the inkfountain device moved to the proximity of the ink fountain roller (theamount of opening of the ink fountain key is set to zero) when the inkfilm thickness in the inking device exceeds a predetermined thicknessduring normal operation of the printing press. In this way, the ink onthe rollers of the inking device is collected into the ink fountain(this will be referred to as “fountain return”) and the ink on therollers of the inking device can therefore be thinly leveled (reset).Hence, in the following printing, the sheet is finely printed owing tothe even ink film thickness. In addition, wasteful consumption of theink is prevented as well.

In the intaglio printing method according to the present invention, theink fountain roller is rotationally driven for a predetermined period oftime with the ink fountain key in the ink fountain device closed (theamount of opening of the ink fountain key is set to zero) after theprinting press is operated but before the sheet is printed. In this way,the ink on the rollers in the inking device is returned into the inkfountain and the ink on the ink fountain roller can therefore be thinlyleveled (reset). Hence, when the sheet is subsequently printed, fineprinting is done owing to the even ink film thickness. That is, problemscaused by ink residues formed on the ink fountain roller are solved.

Moreover, in the intaglio printing press according to the presentinvention, the ink fountain roller is rotationally driven for apredetermined period of time with the ink fountain key in the inkfountain device moved to the proximity of the ink fountain roller (theamount of opening of the ink fountain key is set to zero) when the inkfilm thickness in the inking device exceeds a predetermined thicknessduring normal operation of the printing press. In this way, the ink onthe rollers of the inking device is collected into the ink fountain andthe ink on the rollers of the inking device can therefore be thinlyleveled (reset). Hence, in the following printing, the sheet is finelyprinted owing to the even ink film thickness. In addition, wastefulconsumption of the ink is prevented as well.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] FIG. 1 is a schematic view of the overall structure of anindirect intaglio printing press showing one embodiment of the presentinvention.

[FIG. 2] FIG. 2 is an enlarged view of an inking device section.

[FIG. 3] FIG. 3 is a detailed view of an ink fountain device section.

[FIG. 4A] FIG. 4A is a block diagram for control of fountain returnduring slower operation.

[FIG. 4B] FIG. 4B is a block diagram for the control of the fountainreturn during normal operation.

[FIG. 4C] FIG. 4C is a modification of the block diagram for the controlof the fountain return during the normal operation.

[FIG. 4D] FIG. 4D is a modification of the block diagram for the controlof the fountain return during the normal operation.

[FIG. 4E] FIG. 4E is a modification of the block diagram for the controlof the fountain return during the normal operation.

[FIG. 5] FIG. 5 is a view describing the fountain return.

[FIG. 6] FIG. 6 is a view describing an example of application to adirect intaglio printing press.

[FIG. 7] FIG. 7 is a diagram describing how an ink residue is generated.

MODES FOR CARRYING OUT THE INVENTION

An intaglio printing press according to the present invention will bedescribed below in detail through an embodiment with reference todrawings.

Embodiment

FIG. 1 is a schematic view of the overall structure of an indirectintaglio printing press showing one embodiment of the present invention.FIG. 2 is an enlarged view of an inking device section. FIG. 3 is adetailed view of an ink fountain device section. FIGS. 4A to 4E areblock diagrams for control of fountain return in various situations.FIG. 5 is a view describing the fountain return. FIG. 6 is a viewdescribing an example of application to a direct intaglio printingpress.

The indirect intaglio printing press, whose overall structure is shownin FIG. 1 by reference numeral 1A, mainly includes: a feed device 2configured to feed paper sheets W (see FIG. 7), which are stored asstacked sheets, one by one; a printing unit 3 configured to print thefed paper sheets W; and a delivery device 4 configured to deliver theprinted paper sheets W. The paper sheets W fed one by one from the feeddevice 2 onto a feedboard 11 are each gripped by a gripper of a swingarm pregripper 12 while its movement in the lengthwise direction and thewidthwise direction is restricted by a registration device whoseillustration is omitted.

The printing unit 3 mainly includes: an impression cylinder 13 as atriple-size cylinder; a plate cylinder (intaglio cylinder) 14 as atriple-size cylinder which faces the impression cylinder 13 and on whichthree plates are mounted side by side in the circumferential direction;an ink collecting cylinder 15 as a quadruple-side cylinder facing theplate cylinder 14; five chablon rollers (partial plate cylinders) 16 assingle-size cylinders facing the ink collecting cylinder 15; and inkingdevices 17 configured to supply inks onto the chablon rollers 16.

In FIG. 1, reference numeral 18 denotes a transfer cylinder facing theimpression cylinder 13 and configured to change the grip on the papersheet W from the swing arm pregripper 12 to a gripper of the impressioncylinder 13. Reference numeral 19 denotes a wiping roller contacting theplates of the plate cylinder 14. Reference numeral 20 denotes a deliverycylinder facing the impression cylinder 13, and a delivery chain 22 islaid between a sprocket (not shown) provided coaxially with the deliverycylinder 20 and a sprocket 21 provided in a rear section of the deliverydevice 4.

In the indirect intaglio printing press 1 with the above structure, thepaper sheet W fed onto the feedboard 11 from the feed device 2 istransported while its grip is changed from the swing arm pregripper 12to the gripper of the impression cylinder 13 through the transfercylinder 18. At the same time, the ink of each inking device 17 istransferred onto the ink collecting cylinder 15 through thecorresponding chablon roller 16 and supplied onto the plate surface ofthe plate cylinder 14, and an excess portion of the supplied ink isremoved by the wiping roller 19.

Thus, the paper sheet W transported by being gripped by the gripper ofthe impression cylinder 13 is printed when passing between theimpression cylinder 13 and the intaglio cylinder 14. The grip on thepaper sheet W is then changed to a delivery gripper of the deliverychain 22, and the paper sheet W is transported by the running of thedelivery chain 22 and dropped and piled onto a pile board 23.

Next, the inking device and an ink fountain device, which are thecharacteristic features of the present invention, will be described withreference to FIGS. 2 and 3. As shown in FIG. 2, the inking device 17mentioned above mainly includes : an ink fountain device 25; a ductorroller 27 supported rotatably and contacting an ink fountain roller 26which is a constituent component of the ink fountain device 25; anoscillating roller 28 supported rotatably and axially movably andcontacting the ductor roller 27; and two form rollers 29 contacting theoscillating roller 28 and the chablon roller 16 mentioned above. All therollers from the ink fountain roller 26 to the form rollers 29 (in thisembodiment, the ink fountain roller 26, the ductor roller 27, theoscillating roller 28, and the form rollers 29) are each configured tobe dragged and rotated the others by friction.

The form rollers 29 are retained movably between a throw-on position(shown by solid lines in FIG. 2) at which the form rollers 29 contactthe oscillating roller 28 and the chablon roller 16 and a throw-offposition (shown by dotted lines in FIG. 2) at which the form rollers 29remain contacting the oscillating roller 28 but are thrown off thechablon roller 16.

As shown in FIG. 3, the above ink fountain device 25 includes an inkfountain 30 in which ink I is stored, and the ink fountain roller 26rotatably supported in front of the ink fountain 30. The ink fountain 30is formed by being surrounded by a pair of left and right ink dams 31 (apair disposed side by side in the front-back direction of the sheet ofFIG. 3), a bottom plate 32, ink fountain keys 33, and the peripheralsurface of the ink fountain roller 26, and the ink I is stored therein.

Also, a retaining bar 35 is mounted on an ink fountain key stand 34 insuch a way as to extend in the axial direction of the ink fountainroller 26. There are many ink fountain keys 33 disposed in the proximityof the peripheral surface of the ink fountain roller 26 and providedside by side in the axial direction of the ink fountain roller 26. Afulcrum pin 36 is formed to be as long as the retaining bar 35, and eachink fountain key 33 is pulled by the elastic force of a disc spring 37and retained on the retaining bar 35 with the fulcrum pin 36therebetween. The ink fountain key 33 is provided with a concave groove(not shown) formed in such a circular shape as to be in sliding contactwith a slide surface on the fulcrum pin 36.

Thus, the ink fountain keys 33 are supported on the retaining bar 35swingably about the slide surface of the fulcrum pin 36 as the fulcrumof the swing. Swinging each of the ink fountain keys 33 changes the gapbetween itself and the peripheral surface of the ink fountain roller 26,so that the amount of ink supply is adjusted. The ink fountain keys 33are swung by forward and backward movement (see arrows E, D) of theirrespective ink-fountain-key opening-closing screw rods 38. Eachink-fountain-key opening-closing screw rod 38 moves forward or backwardwhen rotation of an ink-fountain-key adjusting motor (ink-fountain-keyadjusting means) 43 is transferred thereto through a gear mechanism 39.

Moreover, in this embodiment, the indirect intaglio printing press 1Aincludes a control device 40 configured to control the drive of theabove-mentioned ink-fountain-key adjusting motor 43 and alater-mentioned ink-fountain-roller driving motor (ink-fountain-rollerdriving means) 42 in such a way as to rotationally drive the inkfountain roller 26 with each ink fountain key 33 closed for apredetermined period of time after the printing press is operated butbefore the paper sheet W is printed, and also to control the drive of alater-mentioned form-roller throw-on and throw-off device 44 during theabove period, the form-roller throw-on and throw-off device 44 beingconfigured to move the above-mentioned form rollers 29 between thethrow-on position and the throw-off position.

Specifically, as shown in FIG. 4A, a print start switch 41, which isoperated by the operator, inputs a signal into the control device 40,which is a microcomputer or the like, and, in a predetermined time afterreceiving the signal (i.e. in a predetermined period during sloweroperation of the printing press), the control device 40 outputs drivesignals to the ink-fountain-roller driving motor 42, theink-fountain-key adjusting motor 43, and the form-roller throw-on andthrow-off device 44. Note that as the form-roller throw-on and throw-offdevice 44, a device publicly known, for example from Patent Document 1,is used which includes an air cylinder, brackets, and the like.

With the control device 40 configured as above, each ink fountain key 33in the ink fountain device 25 is closed by the ink-fountain-keyadjusting motor 43 through the ink-fountain-key opening-closing screwrod 38 (the amount of opening of the ink fountain key 33 is set to zero)and the ink fountain roller 26, the ductor roller 27, the oscillatingroller 28, and the form rollers 29 are rotationally driven by theink-fountain-roller driving motor 42 at a predetermined rotational speedfor a predetermined period of time after the printing press is operatedbut before the paper sheet W is printed.

Here, while the amount of opening of the ink fountain key 33 is set atzero, the ink fountain key 33 and the ink fountain roller 26 are out ofcontact with each other. A gap G between the ink fountain key 33 and theink fountain roller 26 is very nearly zero (narrow). Hence, the amountof the ink I flowing out of the ink fountain 30 onto the ink fountainroller 26 is not zero but is extremely small, so that the ink I isformed into an extremely thin film on the peripheral surface of the inkfountain roller 26 (see FIG. 5).

Thus, the ink I on the ink fountain roller 26 is returned onto thebottom plate 32 of the ink fountain 30 (this will be referred to as“fountain return”). Specifically, even if ink residues are formed in theinking device 17, the ink I on the ink fountain roller 26, the ductorroller 27, the oscillating roller 28, and the form rollers 29 in theinking device 17 is mostly returned into the ink I stored in the inkfountain 30. Hence, the ink I on the ink fountain roller 26, the ductorroller 27, the oscillating roller 28, and the form rollers 29 is thinlyleveled (reset).

The control device 40 is configured to subsequently control the drive ofthe ink-fountain-key adjusting motor 43 after the “fountain return”performed after the printing press is operated but before the papersheet W is printed, such that the gap G between the ink fountain key 33and the ink fountain roller 26 can be a key opening degree coincidingwith the image information and printing speed.

As a result, in normal operation of the printing press after the sloweroperation, fine printing is performed owing to an even ink filmthickness T. That is, problems caused by ink residues formed on the inkfountain roller 26 are solved.

Also, in this embodiment, during the “fountain return,” the form-rollerthrow-on and throw-off device 44 throws the form rollers 29 off thechablon roller 16. Hence, all the rollers of the inking device 17 fromthe ink fountain roller 26 to the form rollers 29 (in this embodiment,the ink fountain roller 26, the ductor roller 27, the oscillating roller28, and the form rollers 29) are subjected to the “fountain return.”Accordingly, the ink film thickness T is made further even in the inkingdevice 17.

After the “fountain return,” the gap G between the ink fountain key 33and the ink fountain roller 26 is at a key opening degree appropriatefor the image information and printing speed. Hence, the printing pressis ready for the printing to be performed, without an ink residue andwith the ink film thickness T appropriate for the printing.

The control device 40 according to this embodiment is also configured tocontrol the drive of the above-mentioned ink-fountain-key adjustingmotor 43 and ink-fountain-roller driving motor (ink-fountain-rollerdriving means) 42 in such a way as to rotationally drive the inkfountain roller 26 with each ink fountain key 33 closed (moved to theproximity of the ink fountain roller 26) for a predetermined period oftime when the ink film thickness T on the various rollers of the inkingdevice 17 (in this embodiment, the ink fountain roller 26, the ductorroller 27, the oscillating roller 28, and the form rollers 29) exceeds apredetermined thickness during the normal operation of the printingpress (i.e. during the state where the printing is performed), and alsoto control the drive of the form-roller throw-on and throw-off device 44during the above period, the form-roller throw-on and throw-off device44 keeping the above-mentioned form rollers 29 contacting the chablonroller 16 rather than being throw off the chablon roller 16.

Specifically, as shown in FIG. 4B, a reset switch (input switch) 41 a,which is operated by the operator, inputs a signal into the controldevice 40, which is a microcomputer or the like, and, for apredetermined period of time after receiving the signal, the controldevice 40 outputs the above-mentioned drive signals to theink-fountain-roller driving motor 42, the ink-fountain-key adjustingmotor 43, and the form-roller throw-on and throw-off device 44.

Alternatively, instead of the reset switch 41 a, a signal may beinputted into the control device 40 from means for detecting thecondition of the ink film thickness T on the form rollers 29 and thelike, namely, a counter 41 b configured to count the number of printedsheets (see FIG. 4C), a film thickness detector 41 c configured toactually detect the ink film thickness T on the form rollers 29 or thelike (see FIG. 4D), or a check device 41 d configured to check thepresence of a sign of poor printing on the sheet (such as increase inprinting density) (see FIG. 4E). Note that the film thickness detector41 c detects the ink film thickness T on the form rollers 29 or the likeby using a laser displacement gauge, an ultrasonic measurement device,or the like.

With the control device 40 configured as above, when the operatordetermines during the normal operation that the ink film thickness T onthe form rollers 29 and the like has exceeded the predeterminedthickness and thus turns on the reset switch (input switch) 41 a toinput the signal therefrom into the control device 40, each ink fountainkey 33 in the ink fountain device 25 is closed by the ink-fountain-keyadjusting motor 43 through the ink-fountain-key opening-closing screwrod 38 (the amount of opening of the ink fountain key is set to zero),and the ink fountain roller 26, the ductor roller 27, the oscillatingroller 28 and the form rollers 29 are rotationally driven by theink-fountain-roller driving motor 42 for such a predetermined period oftime at such a predetermined rotational speed that the reduced ink filmthickness T will not cause poor printing.

Specifically, during printing, the ink fountain roller 26 isrotationally driven while the ink fountain key 33, which adjusts the gapG between itself and the ink fountain roller 26, is moved to theproximity of the ink fountain roller 26 in accordance with the magnitudeof the ink film thickness T on the various rollers in the inking device17 (in this embodiment, the ink fountain roller 26, the ductor roller27, the oscillating roller 28, and the form rollers 29).

Here, while the amount of opening of the ink fountain key 33 is set atzero, the ink fountain key 33 and the ink fountain roller 26 are out ofcontact with each other. The gap G between the ink fountain key 33 andthe ink fountain roller 26 is very nearly zero (narrow). Hence, theamount of the ink I flowing out of the ink fountain 30 onto the inkfountain roller 26 is not zero but is extremely small, so that the ink Iis formed into an extremely thin film on the peripheral surface of theink fountain roller 26 (see FIG. 5).

Thus, the ink I on the various rollers of the inking device 17 (in thisembodiment, the ink fountain roller 26, the ductor roller 27, theoscillating roller 28, and the form rollers 29) is returned onto thebottom plate 32 of the ink fountain 30 (“fountain return”).Specifically, the ink I on the various rollers of the inking device 17(in this embodiment, the ink fountain roller 26, the ductor roller 27,the oscillating roller 28, and the form rollers 29) is mostly returnedinto the ink I stored in the ink fountain 30 and is therefore thinlyleveled (reset).

Of course, in the intaglio printing press according to the presentinvention, the key opening degree (the amount of opening of the inkfountain key 33) in the state where the ink fountain key 33 is closed(moved to the proximity) is not limited to zero as in this embodiment.For example, the key opening degree in the “fountain return” may be ahalf of (50% less than) the set value of the key opening degree duringthe normal printing operation.

The control device 40 is configured to subsequently control the drive ofthe ink-fountain-key adjusting motor 43 after the “fountain return” suchthat the gap G between the ink fountain key 33 and the ink fountainroller 26 can be a key opening degree coinciding with the imageinformation and printing speed.

Generally, during the normal operation of a printing press, the ink I isnot transferred onto the various rollers in the inking device 17 (inthis embodiment, the ink fountain roller 26, the ductor roller 27, theoscillating roller 28, and the form rollers 29) at positions thatcoincide with the non-printed portions (notched portions and portionswithout images) of the chablon roller 16 and the ink film thickness T islarge there. This makes the ink film thickness T on the various rollers(in this embodiment, the ink fountain roller 26, the ductor roller 27,the oscillating roller 28, and the form rollers 29) uneven, which maynot only cause poor printing but also wasteful consumption of the ink I.

However, by performing the “fountain return” during printing as in thisembodiment, the ink film thickness T is even on the various rollers ofthe inking device 17 (in this embodiment, the ink fountain roller 26,the ductor roller 27, the oscillating roller 28, and the form rollers29) and allows fine printing. Hence, poor printing resulting from theink film thickness T in the inking device 17 is prevented, and also theink film thickness T is not unnecessarily increased and wastefulconsumption of the ink I is therefore prevented as well.

Of course, after the “fountain return,” the gap G between the inkfountain key 33 and the ink fountain roller 26 is shifted to a keyopening degree appropriate for the image information and printing speed.Hence, the normal operation can be continued with the fine ink filmthickness T quickly after the “fountain return.”

In the above embodiment, the example has been described where the“fountain return” is performed without stopping the feed of paper sheetsin the feed device 2 during printing (during the normal operation of theprinting press). However, it is also possible to perform the “fountainreturn” after stopping the feed of paper sheets (sheet feed device 45),discharging all the paper sheets inside the press, and then throwing theform rollers 29 of the inking device 17 off the chablon roller 16.

Also, the above embodiment has been described by taking the indirectintaglio printing press 1A as an example. However, as shown in FIG. 6,the present invention may be applied to a direct intaglio printing press1B in which ink I is transferred onto a chablon roller 16 from an inkfountain device 25 of an inking device 17 and transferred directly ontoan intaglio cylinder 14 from a chablon roller 16 without beingtransferred through an ink collecting cylinder 15. In this way, lowviscosity ink I can be handled. Note that in FIG. 6, the same members asthose in FIG. 1 are denoted by the same reference numerals andoverlapping description thereof is omitted.

Needless to say, the present invention is not limited to the aboveembodiment and various changes such as changes in the structure of theinking device and in the cylinder diameters of the cylinders can be madewithout departing from the gist of the present invention.

In the above embodiment, each ink fountain key is closed during the“fountain return.” However, the amount by which the ink fountain key isclosed (the amount of movement to the proximity) may be set to anysuitable amount. Further, all of the plurality of ink fountain keys maybe moved to the same position or moved in the closing direction (to theproximity) as a whole while maintaining the mutual positionalrelationship that coincides with the image information.

Also, in the above embodiment, each ink fountain key 33 is swung tochange the gap G between itself and the ink fountain roller 26. However,for example, the ink fountain key 33 may be formed in the shape of aflat plate sandwiched between the retaining bar 35 and the bottom plate32, and the gap G between the ink fountain key 33 and the ink fountainroller 26 may be changed by sliding the ink fountain key 33 between theretaining bar 35 and the bottom plate 32. In other words, the inkfountain key and the ink-fountain-key adjusting means in the presentinvention only need be such that the ink fountain key 33 is movable andthe gap G between the ink fountain key 33 and the ink fountain roller 26can be changed by movement of the ink fountain key 33.

EXPLANATION OF REFERENCE NUMERALS

1A indirect intaglio printing press

1B direct intaglio printing press

2 feed device

3 printing unit

4 delivery device

11 feedboard

12 swing arm pregripper

13 impression cylinder

14 plate cylinder (intaglio cylinder)

15 ink collecting cylinder

16 chablon roller (partial plate cylinder)

17 inking device

18 transfer cylinder

19 wiping roller

20 delivery cylinder

21 sprocket

22 delivery chain

23 pile board

25 ink fountain device

26 ink fountain roller

27 ductor roller

28 oscillating roller

29 form roller

30 ink fountain

31 ink dam

32 bottom plate

33 ink fountain key

34 ink fountain key stand

35 retaining bar

36 fulcrum pin

37 disc spring

38 ink-fountain-key opening-closing screw rod

39 gear mechanism

40 control device

41 print start switch

42 ink-fountain-roller driving motor (ink-fountain-roller driving means)

43 ink-fountain-key adjusting motor (ink-fountain-key adjusting means)

44 form-roller throw-on and throw-off device

45 sheet feed device

I ink

P plate

W paper sheet (sheet)

C ink residue

G gap between ink fountain key and ink fountain roller

T ink film thickness on various rollers of inking device

1. An intaglio printing press, including an intaglio cylinder on which aplate is mounted, a wiping roller configured to wipe an excess portionof ink on the plate by contacting the plate on the intaglio cylinder, animpression cylinder configured to print a sheet by facing the intagliocylinder, and an inking device configured to supply ink directly orindirectly onto the intaglio cylinder, the inking device including anink fountain roller, ink-fountain-roller driving means for rotationallydriving the ink fountain roller, an ink fountain a front end of whichfaces the ink fountain roller and which is configured to store ink incooperation with a peripheral surface of the ink fountain roller, an inkfountain key movably supported on the front end of the ink fountain andconfigured to adjust a gap between the ink fountain key and the inkfountain roller, and ink-fountain-key adjusting means for adjusting anamount of movement of the ink fountain key, characterized in that theintaglio printing press comprises a control device configured to controlthe ink-fountain-key adjusting means and the ink-fountain-roller drivingmeans before the sheet is printed, in such a way as to rotationallydrive the ink fountain roller with the ink fountain key closed.
 2. Theintaglio printing press according to claim 1, characterized in that theintaglio printing press is an indirect intaglio printing presscomprising: a plurality of chablon rollers onto which ink is transferredfrom the inking device; and an ink collecting cylinder configured totransfer the ink from the plurality of chablon rollers onto the intagliocylinder.
 3. The intaglio printing press according to claim 2,characterized in that the intaglio printing press further comprises aform-roller throw-on and throw-off device configured to throw formrollers on and off the chablon rollers, and the control device controlsthe form-roller throw-on and throw-off device in such a way as to throwthe form rollers off the chablon rollers, when rotationally driving theink fountain roller with the ink fountain key closed before printing isstarted.
 4. The intaglio printing press according to claim 1,characterized in that the control device controls the ink-fountain-keyadjusting means and the ink-fountain-roller driving means duringprinting in such a way as to rotate the ink fountain roller with the inkfountain key moved to a proximity of the ink fountain roller.
 5. Theintaglio printing press according to claim 4, characterized in that theintaglio printing press further comprises an input switch configured tostart collection of ink, and the control device controls theink-fountain-key adjusting means and the ink-fountain-roller drivingmeans based on the input switch.
 6. The intaglio printing pressaccording to claim 4, characterized in that the intaglio printing pressfurther comprises a counter configured to count the number of printedsheets, and the control device controls the ink-fountain-key adjustingmeans and the ink-fountain-roller driving means based on the counter. 7.The intaglio printing press according to claim 4, characterized in thatthe intaglio printing press further comprises a film thickness detectorconfigured to detect an ink film thickness on the roller of the inkingdevice, the control device controls the ink-fountain-key adjusting meansand the ink-fountain-roller driving means based on the film thicknessdetector.
 8. The intaglio printing press according to claim 4,characterized in that the intaglio printing press further comprises acheck device configured to check a printed sheet, and the control devicecontrols the ink-fountain-key adjusting means and theink-fountain-roller driving means based on the check device.
 9. Anintaglio printing method of printing a sheet by supplying ink from anink fountain onto an intaglio cylinder through an ink fountain rollerwhile passing the sheet between the intaglio cylinder and an impressioncylinder facing the intaglio cylinder, characterized in that theintaglio printing method comprises rotationally driving the ink fountainroller while closing an ink fountain key before the sheet is printed,the ink fountain key being configured to adjust a gap between the inkfountain key and the ink fountain roller.
 10. The intaglio printingmethod according to claim 9, characterized in that the intaglio printingmethod further comprises rotationally driving the ink fountain rollerwhile moving the ink fountain key to a proximity of the ink fountainroller during printing.